Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 865 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.889 − 698 =
2. 2.873 − 437 =
3. 3.878 − 597 =
4. 4.629 − 469 =
5. 5.908 − 349 =
6. 6.325 − 298 =
7. 7.837 − 797 =
8. 8.333 − 299 =
9. 9.520 − 428 =
10. 10.944 − 599 =
11. 11.566 − 298 =
12. 12.693 − 667 =
13. 13.754 − 567 =
14. 14.645 − 498 =
15. 15.990 − 479 =
16. 16.525 − 197 =
17. 17.862 − 799 =
18. 18.858 − 397 =
19. 19.629 − 539 =
20. 20.877 − 197 =
21. 21.839 − 169 =
22. 22.653 − 498 =
23. 23.839 − 799 =
24. 24.950 − 598 =
25. 25.328 − 299 =
26. 26.982 − 397 =
27. 27.321 − 117 =
28. 28.882 − 569 =
29. 29.571 − 428 =
30. 30.765 − 169 =
31. 31.564 − 297 =
32. 32.947 − 597 =
33. 33.641 − 498 =
34. 34.785 − 397 =
35. 35.293 − 249 =
36. 36.565 − 408 =
37. 37.774 − 499 =
38. 38.870 − 457 =
39. 39.843 − 697 =
40. 40.965 − 399 =

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